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Bus naming array

Beginners
Dennis
2015-08-21
2018-09-25
  • Dennis

    Dennis - 2015-08-21

    Hello all,

    This is a very basic question that I'm sure has been answered a number of times, but my searching skills are lacking. Therefore, I will be creating a new thread to ask it.

    When defining a single phase transformer terminal connections as an array as such:

    New Transformer.A **Buses=[BusA.3 BusB]** XfmrCode=XfrmrCodeX
    

    BusA.3 is winding 1, with connections on BusA: Node 3 to ground
    BusB is winding 2, with connections on BusB: Node X? to Node Y?... what is Node X and Node Y exactly?

    I don't know how winding 2 is defined. Any help is appreciated, as always

     
  • Davis Montenegro

    Hi,

    Winding 2 is connected to BusB starting in node 1 to ground and acording to the number of phases of the device; this is, if you transformer is a single phase device the connection will be BusB.1, if it's three phase the connection will be BusB1.2.3. When you don't specify the connection to the bus, OpenDSS assummes the connection starting from the first node available in the bus and the number of phases of the device.

    Bes regards

    Davis

     
  • Roger Dugan

    Roger Dugan - 2015-08-21

    Both terminals of the transformer will have 2 conductors to connect to some node. The default template for the bus connection of a 1-phase device is Busname.1.0.0.0.... So if you don't specify anything, you'll get BusB.1.0 for the second winding. I always recommend explicitly spelling out the connections so that there is no ambiguity in case you really wanted something like this:

    New Transformer.A Buses=[BusA.3.0 BusB.3.0] XfmrCode=XfrmrCodeX

    or this:

    New Transformer.A Buses=[BusA.3.0 BusB.1.2] XfmrCode=XfrmrCodeX

     
  • Kevin Abraham

    Kevin Abraham - 2018-09-25

    Hello,
    I too had a follow up question regarding this. I was going through the manual and the terms "nodes", "terminals", and "phases" were confusing me a litle bit (in terms of naming conventions for OpenDSS that is). Please do let me know if there are any more documents I could refer to, to clarify this matter.
    For instance, for the code below does it mean that winding 1 of the transformer is connected to a single phase bus with connections from 1 to ground, and winding 2 is connected to a 2 phase bus?

    new transformer.TRA1 phases=1 windings=2 
    ~ wdg=1 conn=wye bus=A1.1 kv=(25 1.73205 /)  kva=75
    ~ wdg=2 conn=delta bus=subA_11.1.2 kv=0.240  kva=75
    

    Any comments are appreciated!
    Thanks

     
  • Roger Dugan

    Roger Dugan - 2018-09-25

    Each winding of the 1-phase transformer will have two conductors to connect. The kV property for each winding should be then 1 pu voltage that would appear across the two conductors.

    The connection of Wdg=1 is A1.1.0, The 0 is implied if not specified.

    Wdg 2 is connected between phases (nodes) 1 and 2 of the bus SubA_11.

     

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